The present invention relates to a method of producing a plasma display panel (xe2x80x9cPDPxe2x80x9d) substrate and, more particularly, to a method of producing barrier ribs for PDP substrate, capable of providing an image having high brightness and high contrast.
Various developments have recently been made in the field of flat panel display devices capable of displaying large images. Among them are PDPs. Generally, a PDP is equipped with a substrate composed of a pair of glass flat panels (glass bases) facing each other and separated by a distance via barrier ribs each having a predetermined dimension (also referred to as a rib, bulkhead or barrier). In PDP substrates with such constructions, the space between the glass panels is partitioned in an air-tight manner to form a plurality of discharge display cells capable of containing an inert gas such as neon, helium or xenone as a discharge gas.
Technical problems of PDP include displaying images having high brightness and high contrast. Typically, the ribs on the back panel are white, causing light emitted from a fluorescent material due to discharge of the above-described rare gas to be reflected. This can be effective in increasing brightness. However, reflection of external light on the rib tops can greatly reduce contrast.
As a measure for simultaneously satisfying both requirements of high brightness and high contrast, Unexamined Patent Publication (Kokai) No. 10-321143 has suggested a structure wherein colored patterns for respective luminescent colors are formed on a front panel at the positions corresponding to the luminescent colors, and black strips are provided at the positions on the front panel contacting the rib tops as a boundary of the colored patterns. Drawbacks of this approach include many complicated processing steps, high size and position accuracy requirements, and the like.
Unexamined Patent Publication (Kokai) No. 10-172442 discloses a PDP substrate comprising a glass base and ribs formed on the glass base, wherein the rib tops are black and the rib bottoms are white or transparent. This inhibits external light reflection from the rib tops for increased contrast while allowing some reflection of emitted light by the bottom rib portions. According to the above publication, screen printing and photolithography are employed to form a bulkhead for such a PDP substrate. These methods have drawbacks such as requiring time consuming drying steps before coating each next layer. Using screen printing methods, it is difficult to maintain size and shape accuracy. Photolithograpy methods require several developing, coating and exposure steps.